1. Field of the Invention
The present invention relate to a distribution apparatus for distributing liquid samples used in biochemical and the like fields, a method of the distribution and a method of fitting distribution tips.
2. Description of the Related Art
Distributing liquid samples or reagents in small quantities to sample vessels, or a microplate, is a common operation practiced during experimentation or analysis in the biochemical field, for example. The distribution is performed by sucking/discharging a certain liquid using a distribution nozzle. The distribution nozzle is usually fitted with a disposable distribution tip, which is replaced with a new one at any time whenever necessary.
The distribution tip is fitted to the distribution nozzle by inserting the lower end of the latter into a pipet-shaped opening of the distribution tip at the upper end. Fixing of a distribution tip to a distribution nozzle solely depends on the elastic fastening force of an elastic resin-made distribution tip surrounding the lower end of the distribution nozzle. As a result, if an external force is applied to a distribution tip during, or after, a fitting operation, the distribution tip may not be attached straight relative to the distribution nozzle, and the bottom end of the distribution tip will be dislocated. A small amount of dislocation may not cause any material trouble if the diameter of a well in the receiving microplate is sufficiently large. Namely, a small amount of dislocation is acceptable so long as the distribution tip is inserted in the well, and the sucking/discharging of liquid is performed without having any difficulty.
Recently, however, the diameter of wells on a microplate is getting smaller reflecting the general trend of pursuing a higher efficiency in the experimental work and a reduced consumption of samples and reagents. When such a microplate having the small wells is used on a conventional distribution apparatus, the distributing operation may not be performed satisfactorily because of a displaced location of the distribution tip.
The present invention addresses the above problem and offers a distribution apparatus in which the inconveniences stemming from a dislocated distribution tip are curtailed. The methods of distribution, as well as methods of fitting the distribution tip are also offered in the present invention.